Pain is divided into two types based on how long it lasts. Acute pain develops immediately following injury. Pain that lasts for longer than about three months is defined as chronic. Chronic pain does not go away even when the injury that caused it has had time to heal.

The Nervous System and How It Processes Pain

The nervous system consists of the brain, spinal cord, and peripheral nerves. Its job is to process incoming information and generate a response. While the process seems straightforward, the nervous system is actually the most complex organ system in your body. Throughout your body, there are nerve fibers and nerve endings that send signals to the spinal cord and brain. Nerve endings are sensory receptors that give us information regarding our environment and allow us to experience the world around us. All the sensations you experience start out as the stimulation of a specific receptor somewhere in the body. Some of them are vital for protecting the body from potential harm by transmitting pain, such as the pain that warns us that our hand is being damaged by a hot pan on the stove.

When the Nervous System Malfunctions

When the nervous system functions normally, there is a predictable sequence. An injury occurs. The pain begins and worsens over a period of time and then it lessens and disappears as the injury heals. When this system malfunctions the pain pathways are left “turned on” and remain hypersensitive. Essentially, the central nervous system can learn how to experience pain. After it learns this, almost any stimulation can be painful. In this state, signals that wouldn’t otherwise be experienced as painful can be very painful. This can persist for quite some time after a painful experience. It can also be activated by stress or fear.